You're off to a nice start, I can't give critique on the dragons 'cuz mythical creatures defy the rules of anatomy, though the symbols on the Magician Dragon are unnatural and out of place. To combat that you can try a 3D tattoo approach.

The thumb on the hand isn't full enough, it needs to be a bit bigger, you can also move it a tad more up.

Other than that all I can say is practice more with your pencil so you can reduce the scratchyness of the lines.

I can't give critique on the dragons 'cuz mythical creatures defy the rules of anatomy,

Kagepen. Here are some links and pictures to help you lrn2anatomy

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Sorry about the crappy scan, books are a pain. Anyways the point here is that all mythical creatures are either based on one type of animal or a combination of several. Any artist who knows what they are doing will have studied the anatomy for the creature that they are drawing.

For example:

Serpent dragons you study SNAKE anatomy... Or lizard dragons you study Lizard anatomy. if you want to add wings you study BIRDS....

a mythical creature that doesn't follow the basic laws of anatomy just doesn't look cool. It looks weird and like a five year old drew it.

Everlastin your dragon isn't too bad. it needs work. I'd say if you want it to be serpentine study a snake because right now it's like a salamander on steroids. Which you can work with.